Struct RdbcItemReaderBuilder 

pub struct RdbcItemReaderBuilder<'a, I> { /* private fields */ }

Available on crate feature rdbc only.

Unified builder for creating RDBC item readers for any supported database type.

This builder provides a consistent API for constructing database readers regardless of the underlying database (PostgreSQL, MySQL, or SQLite). Users specify the database type and connection pool, and the builder handles the creation of the appropriate reader implementation.

Type Parameters

• I - The item type that implements the appropriate FromRow trait for the database

Examples

PostgreSQL

use spring_batch_rs::item::rdbc::{RdbcItemReaderBuilder, DatabaseType};
use sqlx::PgPool;

let pool = PgPool::connect("postgresql://user:pass@localhost/db").await?;

let reader = RdbcItemReaderBuilder::<User>::new()
    .postgres(pool)
    .query("SELECT id, name FROM users")
    .with_page_size(100)
    .build_postgres();

MySQL

use spring_batch_rs::item::rdbc::{RdbcItemReaderBuilder, DatabaseType};
use sqlx::MySqlPool;

let pool = MySqlPool::connect("mysql://user:pass@localhost/db").await?;

let reader = RdbcItemReaderBuilder::<Product>::new()
    .mysql(pool)
    .query("SELECT id, name FROM products")
    .with_page_size(100)
    .build_mysql();

SQLite

use spring_batch_rs::item::rdbc::{RdbcItemReaderBuilder, DatabaseType};
use sqlx::SqlitePool;

let pool = SqlitePool::connect("sqlite::memory:").await?;

let reader = RdbcItemReaderBuilder::<Task>::new()
    .sqlite(pool)
    .query("SELECT id, title FROM tasks")
    .with_page_size(100)
    .build_sqlite();

Implementations

impl<'a, I> RdbcItemReaderBuilder<'a, I>

pub fn new() -> Self

Creates a new unified reader builder with default configuration.

pub fn postgres(self, pool: Pool<Postgres>) -> Self

Sets the PostgreSQL connection pool and database type.

Arguments

• pool - The PostgreSQL connection pool

Returns

The updated builder instance configured for PostgreSQL

pub fn mysql(self, pool: Pool<MySql>) -> Self

Sets the MySQL connection pool and database type.

Arguments

• pool - The MySQL connection pool

Returns

The updated builder instance configured for MySQL

pub fn sqlite(self, pool: Pool<Sqlite>) -> Self

Sets the SQLite connection pool and database type.

Arguments

• pool - The SQLite connection pool

Returns

The updated builder instance configured for SQLite

pub fn query(self, query: &'a str) -> Self

Sets the SQL query for the reader.

The query should not include LIMIT/OFFSET clauses as these are handled automatically when page_size is configured.

Arguments

• query - The SQL query to execute

Returns

The updated builder instance

pub fn with_page_size(self, page_size: i32) -> Self

Sets the page size for paginated reading.

When set, the reader will fetch data in chunks of this size to manage memory usage efficiently.

Arguments

• page_size - Number of items to read per page

Returns

The updated builder instance

impl<'a, I> RdbcItemReaderBuilder<'a, I>

where for<'r> I: FromRow<'r, PgRow> + Send + Unpin + Clone,

pub fn build_postgres(self) -> PostgresRdbcItemReader<'a, I>

Builds a PostgreSQL reader.

Returns

A configured PostgresRdbcItemReader instance

Panics

Panics if PostgreSQL pool or query are missing

impl<'a, I> RdbcItemReaderBuilder<'a, I>

where for<'r> I: FromRow<'r, MySqlRow> + Send + Unpin + Clone,

pub fn build_mysql(self) -> MySqlRdbcItemReader<'a, I>

Builds a MySQL reader.

Returns

A configured MySqlRdbcItemReader instance

Panics

Panics if MySQL pool or query are missing

impl<'a, I> RdbcItemReaderBuilder<'a, I>

where for<'r> I: FromRow<'r, SqliteRow> + Send + Unpin + Clone,

pub fn build_sqlite(self) -> SqliteRdbcItemReader<'a, I>

Builds a SQLite reader.

Returns

A configured SqliteRdbcItemReader instance

Panics

Panics if SQLite pool or query are missing

Trait Implementations

impl<'a, I> Default for RdbcItemReaderBuilder<'a, I>

fn default() -> Self

Returns the “default value” for a type.